t-sql-json-and-openjson

Queries and stores JSON on Azure SQL Database using the native json type, a JSON index, and OPENJSON with an explicit WITH schema, instead of the older nvarchar(max) plus JSON_VALUE pattern the training data is full of. Use when asked to "store JSON in SQL", "query a JSON column", "shred a JSON array into rows", "flatten this payload into a table", "index a JSON property", "should this be nvarchar(max) or the json type", "parse the API response we saved", or when JSON_VALUE, JSON_QUERY, JSON_MODIFY, ISJSON, OPENJSON, JSON_OBJECT or JSON_ARRAYAGG appears in a query being written or reviewed; and when a JSON lookup returns NULL for a value that is visibly present, or invalid JSON reached a column that nothing rejected. Where a document column belongs in a table design is design-azure-sql-schema, and general T-SQL dialect is t-sql-correctness.